This subproject is one of many research subprojects utilizing the resources provided by a Center grant funded by NIH/NCRR. The subproject and investigator (PI) may have received primary funding from another NIH source, and thus could be represented in other CRISP entries. The institution listed is for the Center, which is not necessarily the institution for the investigator. We propose to employ molecular dynamics simulations to elucidate, at the atomistic-level, the structural bases and biophysical mechanisms of mechanical regulation of three molecular systems: selectins, integrins, and platelet glycoprotein Ib (GPIb) interacting with their respective ligands.All simulations will be run using the molecular simulation software NAMD. We have used NAMD to perform preliminary simulations of these three systems and have obtained exciting preliminary results.